It's all speculations now. But I think the consensus is that early AM2 processors won't be a huge leap compared to the current 939.

If you are not in a hurry, you can always wait for it, and decide when they are released. Chances are, they will be a cost premium over the 939, and you would be able to get one for cheaper then (knowing of course, that it is end of the line - but should hold its own until the next upgrade).